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// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
// error-pattern:thread '<main>' panicked at 'shift operation overflowed'
// compile-flags: -C debug-assertions
// This function is checking that our (type-based) automatic
// truncation does not sidestep the overflow checking.
#![warn(exceeding_bitshifts)]
fn main() {
// this signals overflow when checking is on
let x = 2_i8 >> 17;
// ... but when checking is off, the fallback will truncate the
// input to its lower three bits (= 1). Note that this is *not*
// the behavior of the x86 processor for 8- and 16-bit types,
// but it is necessary to avoid undefined behavior from LLVM.
//
// We check that here, by ensuring the result is not zero; if
// overflow checking is turned off, then this assertion will pass
// (and the compiletest driver will report that the test did not
// produce the error expected above).
assert_eq!(x, 1_i8);
}
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